Memoirs of the Geological Survey of India . ed, none of the included fragments showed anysigns of having been exposed to great heat. The included blocks consistof a hard, highly hornblendic schist, which seems generally to resistatmospheric influences far better than does the rock in which they areinclosed. Occasionally, however, they appear to have weathered morerapidly, and to have given rise thereby to cavities much resembling potholes. Good examples of such included masses may be seen to advantage at ^ . 1 ,. Yellavanasur, in the old mud fort, also at Cunatur Quasi-conglomeratic ? ^®^^ hil
Memoirs of the Geological Survey of India . ed, none of the included fragments showed anysigns of having been exposed to great heat. The included blocks consistof a hard, highly hornblendic schist, which seems generally to resistatmospheric influences far better than does the rock in which they areinclosed. Occasionally, however, they appear to have weathered morerapidly, and to have given rise thereby to cavities much resembling potholes. Good examples of such included masses may be seen to advantage at ^ . 1 ,. Yellavanasur, in the old mud fort, also at Cunatur Quasi-conglomeratic ? ^®^^ hill, rive miles east-north-east of Tirukovilur, the granitoid rocks assume, near to the village of Chittanur, quite a conglo-meratic appearance; so numerous are the included fragments which in all( 300 ) CirAr. IV. 1.] METAMOIIPIIIC HOCKS. 79 cases are of horublendic schist of black or greenish-black colour. Theaccomj)anying sketch (Fig. 2) shows a portion of the bed in question^ with Fig. 2.—Quasi-conglomeratic gxeiss, nkau several included fragments^ the largest of which measures about 1 foot 10inches in length. The same pseudo-conglomeratic nature of the gneissbeds may also be well observed at Arkadu^ wdiere the rocks comedoAvn to the bank of the Punniar river in a well-marked ridge ; also atPuragil^ on the banks of the Teringee Aur^ a small river rising near Trino-malli and entering the Punniar opposite to Tirukovilur. Lastly, we haveto enumerate a very clear exhibition of included blocks at Seganankottei^about half way between Tirukovilur and Tiagar. Owing to the peculiar con-stitution of the greater part of the rocks just described, the greater partof the area occupied by them is covered by a very sandy soil, generallyof very pale colour, but here and there passing into decided red soil occurs no where but at the southern extremity of the por-phyritic rock districts. The sandy soil consists mainly of silex, witha smaller proportion of decomposing
Size: 2157px × 1159px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectgeology, booksubjectminesandmineralr
